In processing a silver halide color photographic material containing yellow, magenta and cyan dye forming couplers, a system of forming a color image by a subtractive color process using a coupling reaction of the coupler with an oxidation product of an aromatic primary amine developing agent to form the corresponding dyes is most widely utilized.
Recently, studies for improvement of dye forming couplers have been effected actively in the technical field of preparing silver halide color photographic materials for the purpose of improving the color reproducibility and of improving the fastness of the images. However, it is hard to say that sufficient improvement has heretofore been attained because of the limitation of color developing agents. Regarding cyan couplers, phenol or naphthol couplers have been used essentially up to this time. However, the dyes to be formed from these couplers often have an unwanted absorption in the blue and green ranges, which is a great bar to improvement of the color reproducibility.
Recently, studies of new cyan dye forming couplers having a skeleton of a nitrogen-containing heterocyclic structure have been carried out actively, and various heterocyclic compounds have been proposed. For instance, JP-A-63-226653 (corresponding to U.S. Pat. No. 4,818,672) mentions diphenylimidazole couplers; and JP-A-63-199352, 63-250649 (corresponding to U.S. Pat. No. 4,916,051), 63-250650 (corresponding to U.S. Pat. No. 4,916,051), 64-554 (corresponding to U.S. Pat. No. 4,873,183), 64-555 (corresponding to U.S. Pat. No. 4,873,183), 1-105250 and 1-105251 mention pyrazoloazole couplers. (The term "JP-A" as used herein means an "unexamined published Japanese patent application".) All of these couplers are said to have an improved color reproducibility, and they are characterized by an excellent absorption characteristic.
However, these couplers have a drawback that the dyes to be formed therefrom absorb short-wave lights and are hardly fast to heat and light. In addition, they have another serious problem for practical use in that the coupling activity of the couplers is small.
JP-A-62-278552 mentions pyrroloimidazole magenta couplers. However, the couplers from dyes which absorb short-wave lights, as they have no electron-attracting group at the 6- and 7-positions, and they could not be cyan couplers.